Write the chemical formula of calcium carbonate.

SYMBOL	Ca	${\mathrm{CO}}_3$
CHARGE	+2	-2

[1 Marks]
After criss-crossing the symbol and charge, we get the formula as ${\mathrm{Ca}}_2{\left({\mathrm{CO}}_3\right)}_2$.We further simplify it by dividing it with the common factor 2 and the chemical formula of calcium carbonate is ${\mathrm{CaCO}}_3$
[1 Marks]